HDMI cameras with lenses that match the field of view of the HMD are installed. The output of the HDMI cameras goes into a broadcast-quality video mixer that accepts the camera video as well as video from the image-generation PC. “Green screen” or other type of video mixing accounts for low-latency, high frame-rate video that does not impact the performance of the rendering PC

USB3/GigE cameras

USB3 or GigE cameras are installed with lenses that match the field of view of the HMD. The output of these cameras goes into the PC for processing, image recognition or mixing with the rendered images.